2016 sees no increase in barn owl rodenticide residues

17 Oct 2016 sees no increase in barn owl rodenticide residues

No significant changes have been detected in barn owl liver residues of rodenticide between 2016 and a seven-year baseline. This comes from independent analysis by the Centre for Ecology & Hydrology (CEH) of barn owl livers supplied from the Predatory Birds Monitoring Scheme, a citizen science project.

As a widespread predator of small mammals in rural areas, the barn owl is the UK Rodenticide Stewardship Regime’s sentinel species for rodenticide residues in non-target
species. Overall, 78% of owls last year had detectable residues of one or more second generation anticoagulant rodenticide (SGAR).

In both 2016 and the 2006-2012 baseline period, rodenticides detected most frequently were bromadiolone, difenacoum and brodifacoum. Except for a decline in low level residues of difenacoum, there was no significant change in almost all indicators used to assess exposure of barn owls to SGARs.

This CEH analysis is a core element of rodenticide stewardship monitoring procedures, according to Dr Alan Buckle, chairman of the Campaign for Responsible Rodenticide Use. CRRU is responsible to HSE for the stewardship regime’s implementation.

“Bearing in mind that the regime only became effective mid-2016, it is early days yet,” says Dr Buckle. “But clearly, it is also welcome that no surprise changes have been found by CEH, using exactly the same analytical methods in both periods.”